1. Field of the Invention
This invention relates to an apparatus comprising a photoconductor belt guided around a drum for an electrophotographic copying apparatus, more especially to an apparatus with a replaceable, photoconductor belt guided around a revolvable drum in an electrophotographic copying apparatus, which belt extends through an aperture in the shell or circumferential wall of the drum parallel to the axis of the drum and over the periphery thereof and also extends through this aperture into the interior of the drum.
2. Description of the Prior Art
In German published application No. P 20 01 550.3, an electrophotographic copying apparatus has been proposed having a cylindrical drum in the interior of which there are arranged a supply roller and a take-up roller for an organic photoconductor belt. Between the take-up roller and the apparatus there is a gear unit which, when it is engaged, brings about as a result of the rotation of the drum a rotation of the take-up roller which transports the photoconductor belt relative to the drum. In this apparatus, the need for a drive motor in the drum to transport the photoconductor belt is dispensed with since the photoconductor belt is transported by the rotation of the drum via the gear unit.
Another type of copying apparatus is shown in German examined and published application No. 1 522 151, wherein a surface coated with light-sensitive material is guided from a feed spool arranged inside the drum through slots onto the outer side of the drum and from there back again to a take-up spool likewise provided inside the drum. A coupling is provided in this between the take-up spool and its drive shaft which may be actuated via a rod.
In other proposed constructions, difficulties occur in sealing the apertures on the periphery of the drum through which the photoconductor belt is guided out of the interior of the drum and then back again into the drum. To overcome these problems, complicated closure members are provided for the apertures arranged on the shell of the drum, the apertures generally being in the form of slots. These closure members are matched very precisely to the curvature of the shell of the drum and protect the interior of the drum against penetration of developer material. Because of the accurate matching of the closure member to the shell of the drum and of the need for a good sealing of the interior of the drum, they are of complex construction and require accurate manufacturing processes.
A further drawback of many known devices is that the closure members require additional space for installation so that not all the periphery of the drum is available for copying purposes.